1. Field of the Invention
The present invention relates to a maintenance apparatus, a liquid ejection apparatus and a nozzle surface maintenance method, and more particularly to technology for maintaining the liquid ejection surface of a liquid ejection head.
2. Description of the Related Art
In general, an inkjet recording apparatus which forms a desired image by ejecting ink droplets from a head onto a recording medium is widely used as a generic image forming apparatus. In an inkjet recording apparatus, when ink, dust, or the like which has been scattered during ejection adheres to the nozzle surface of a head, then the ink ejection direction may deflected so that displacement can occur in the ink depositing positions, and a prescribed amount of ink may not be ejected from the nozzles, so that ejection abnormalities may occur. Consequently, an inkjet recording apparatus is composed in such a manner that the adhering material which is attached to the nozzle surface of the head is removed at periodic intervals.
A lyophobic film is formed on the nozzle surface of the head, with a view to maintaining prescribed ejection performance. When the nozzle surface is wiped by means of a blade, in order to remove the adhering material on the nozzle surface, the lyophobic film on the nozzle surface may be damaged, and this degradation of the lyophobic film may cause a decline in the ejection performance. A variety of methods which carry out a wiping process after wetting the nozzle surface have been proposed as a countermeasure to this.
Furthermore, Japanese Patent Application Publication No. 2005-96125 discloses a method for cleaning a nozzle plate in which a cleaning plate is disposed at a position opposing the nozzle plate, a solution, such as an ink, is filled in between the nozzle plate and the cleaning plate, and by then increasing the distance between the nozzle plate and the cleaning plate, the solution present between the nozzle plate and the cleaning plate is moved to the cleaning plate, and hence the nozzle plate is cleaned without damaging the nozzle plate.
However, in a method which wets the nozzle surface and then wipes the nozzle surface using a blade, generally, the wetting process requires approximately the same amount of processing time as the wiping process, and therefore approximately twice the processing time is required in comparison with a method which carries out a wiping process only. When it is sought to wet the nozzle surface in a short space of time, it is necessary to make the size of the apparatus used to carry out the wetting process correspond to the size of the head, and hence the apparatus used for the wetting process becomes large in size.
Furthermore, if it is sought to carry out the wetting process in a short period of time, non-uniformities may occur in the wetting of the nozzle surface, and this is undesirable from the viewpoint of protecting the lyophobic film. In particular, in cases where a full line type of head is provided, it is desirable to prevent the increase in the wetting process time and the size of the apparatus used to carry out the wetting process.
Furthermore, if the invention described in Japanese Patent Application Publication No. 2005-96125 is applied to a full line head, then problems of the following kinds arise.
If the length of the cleaning plate is shorter than the length of the line head in the lengthwise direction, then it is necessary to repeat the same process a plurality of times in order to carry out maintenance of the whole head. On the other hand, when the cleaning plate is composed to a length which corresponds to the length of the line head in the lengthwise direction thereof, if it is sought to carry out the maintenance of the whole head in one step, then although this contributes to shortening the processing time, the cleaning plate and the movement mechanism of the cleaning plate become large in size, and consequently, the overall size of the apparatus increases and furthermore, this leads to increase in the overall costs of the apparatus.
Moreover, in the invention described in Japanese Patent Application Publication No. 2005-96125, there is no flow in the solution which is present between the nozzle plate and the cleaning plate, and hence there is a concern that when the ink of increased viscosity adhering to the nozzle surface and the adhering material caused by the ink are cleaned, only a diffusing action serves to promote the dissolution of these ink and adhering material, and hence the adhering material cannot be dissolved in a short period of time, and the time required for cleaning (maintenance time period) becomes long.
Moreover, in the method illustrated in FIGS. 3(a) to 3(f) in Japanese Patent Application Publication No. 2005-96125, there is also a possibility that since the cleaning plate is tilted when the solution present between the nozzle plate and the cleaning plate is moved toward the cleaning plate, the solution spreads out over the cleaning plate, and the interior of the apparatus may be soiled by the solution which has dropped outside the cleaning plate therefrom. Furthermore, in the method illustrated in FIGS. 4(a) to 4(d) in Japanese Patent Application Publication No. 2005-96125, since the cleaning plate is moved in parallel, then there is a possibility that the nozzle surface can become soiled due to the adhering material, which has been moved into the solution on the cleaning plate, becoming reattached to the nozzle surface. In other words, in the methods illustrated in FIGS. 3(a) to 3(f) and FIG. 4(a) to 4(d) of the Japanese Patent Application Publication No. 2005-96125, in any case, it is difficult to clean the nozzle surface without soiling the nozzle plate or the interior of the apparatus, or to recover the solution used for cleaning the nozzle plate.